Climate change driving Michigan mam...( ANN ARBOR Mich.---Some Michigan mamm...)

ANN ARBOR, Mich.---Some Michigan mammal species are rapidly expanding their ranges northward, apparently in response to climate change, a new study shows. In the process, these historically southern species are replacing their northern counterparts.

The finding, by researchers at the University of Michigan, Michigan State University and Ohio's Miami University, appears in the June issue of the journal Global Change Biology.

"When you read about changes in flora and fauna related to climatic warming, most of what you read is either predictive---they're talking about things that are going to happen in the future---or it's restricted to single species living in extreme or remote environments, like polar bears in the Arctic," said lead author Philip Myers, professor of ecology and evolutionary biology at U-M. "But this study documents things that are happening right now, here at home."

What will be the ultimate impact of Michigan's changing mammal communities?

"We're talking about the commonest mammals there, mammals that have considerable ecological impact," Myers said. "They disperse seeds, they eat seeds, they eat the insects that kill trees, they disperse the fungus that grows in tree roots that is necessary for trees to grow, and they're the prey base for a huge number of carnivorous birds, mammals and snakes. But we don't know enough about their natural history to know whether replacing a northern species with a southern equivalent is going to pass unnoticed or is going to be catastrophic. It could work either way.

"What we can say is that the potential is there for serious changes to happen, and it would be really smart of us to figure it out, but that will require a lot of detailed, focused ecological research."

In the study, Myers and coworkers analyzed distribution and abundance records of opossums and eight species of small forest rodents. In addition to data collected by live-trapping animal
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